<div class="show-box">
  <span>{{ countStr }}</span>
</div>
<div>
  <button *ngIf="!isRunning" nz-button nzType="primary" (click)="start()">{{ startBtn }}</button>
  <button *ngIf="isRunning" nz-button nzType="primary" (click)="stop()" >{{ stopBtn }}</button>
  <button nz-button nzType="primary" (click)="reset()" >{{ resetBtn }}</button>
</div>
